The use of algae as a feed for animals has the potential to play a big role in limiting global carbon emissions while also providing the world with more sustainable protein sources, according to a new study published in Carbon Balance and Management. In fact, the authors find that algaculture combined with a modest amount of carbon capture and sequestration could even help bring atmospheric carbon concentrations down to preindustrial levels by the end of the century.
The study, ‘New feed sources key to ambitious climate targets,’ quantifies the emissions reduction potential of using algae as a feedstock by modeling the social, environmental and economic impacts of various technology development scenarios.
The detailed analysis shows that cultivating algae for use as animal feed would have a significant effect on emissions at any scale. Even without the application of CCS the use of algae as animal feed could be expected to limit global temperature change by as much as 0.7° C by the year 2100. That’s quite a large portion of the temperature changes that are expected to occur due to climate change without significant mitigation efforts.
The promise of algae-based feeds exceeds that of other biomass solutions, which all too often face competition for arable land and freshwater supplies. Algae, on the other hand, can be grown on marginal lands, using saltwater or wastewater, and produce yields many times that of traditional crops.
The bottom line for agriculture is that algae-based feeds, which have been proven to be equal to other feeds in nutritional value and digestibility, could free large swaths of arable land while addressing the food security issues that come with a growing global population.
Based on feasible costs, the authors estimate that algae could have supplied 40% of global feeds in 2013 for between $420-920 billion USD (2013), highlighting as a comparison the $550 billion USD (2013) given in fossil fuel subsidies that year.
While the authors do site some challenges that come with deploying new technology, such as the expansion of carbon capture and storage and production of algae at a large scale, they highlight the fact that the use of algae as a feedstock can have an impact on virtually any scale and that the effort would be technologically feasible.
In the words of the authors, algae-based animal feed is a “promising and simultaneous solution to food security and climate change and these systems merit greater attention and closer scrutiny than they have thus far received.”
For more information about the study and its authors, visit the Carbon Balance and Management website.
Photo credit: Walsh et al., New Feed Source Key to Ambitious Climate Targets. Carbon Balance and Management. 2015. Figure 4.